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Caption

Penicillium notatum. Macrophotograph of a petri dish culture of the fungus Penicillium notatum growing on Whickerham's agar. At right, the fungal mycelium is seen, with new growth (green) on the edges. Penicillium notatum was the species of fungus which led Alexander Fleming to discover the antibiotic penicillin. Fleming found, quite by accident, that this fungus inhibits the growth of bacteria and he subsequently used it to produce the first antibiotic drug. There are now many types of penicillin drug, used to treat bacterial infections such as tonsillitis, bronchitis, pneumonia, and the sexually transmitted diseases of syphilis and gonorrhoea.